The hand manipulation of balls is well known as an exercise activity and also to calm the nerves. Rubber balls are often sold for that purpose, or solid balls like the ball bearings that the character Caption Queeg habitually manipulated in The Cain Mutiny may be employed.
Additionally, the exposure of body parts to magnetic fields has long been used to relieve arthritis-like pain. Magnetic straps for wrists, ankles, and the back as well as shoe insoles and magnetic blankets enjoy substantial sales. Medical studies have established therapeutic value for exposure of body parts to magnetic fields, usually attributed to the relative movement and resulting interaction between the blood flowing in the body, which is weakly conductive of electric currents, and the magnetic fields with the two interacting to generate heat and the like.
Separately, copper articles which are supported against the skin are recognized to create compounds which are absorbed into the skin and provide the numerous therapeutic benefits known to be produced by copper trace elements in the body.